1. Field of the Invention
This invention relates to an automatically controlled manually steerable vehicle. In one of its aspects, the invention relates to a power steering means for manually controlling a vehicle with an automatically controlled system.
2. State of the Prior Art
Various service vehicles have been provided with automatic controls so that they are driven on a predetermined guide path in a programmed manner. In such vehicles, the guide paths, such as reflected guide lines or electrically detectable guide wires are positioned on or in the floor. For example, in U.S. Pat. No. 3,628,624 to Wesener, issued Dec. 21, 1971, a vehicle which follows a predetermined guide path has a control panel at the front end of the vehicle for presetting a reader to respond to code markings along the guide path.
An automatically controlled vehicle with a manual control mode is disclosed in the U.S. Pat. to Kohls, 3,557,893, issued Jan. 26, 1971. In the Kohls vehicle, a tiller, pivotably mounted on a vertical steering shaft, is biased to a normally inoperative vertical position. Movement of a tiller downwardly to a horizontal operative position deactivates the automatic steering system, disconnects the steering servomotor, and activates a control unit operated by the handle on the tiller for propulsion regulation and steering of the vehicle. The Kohls system thus has a completely manual steering system which might be somewhat difficult when the vehicle is heavily loaded and traveling on carpeted surfaces.